Liquid reactive polymers

ABSTRACT

Terminally unsaturated liquid epihalohydrin polymers are produced by polymerizing at least one epihalohydrin using hydroxyalkyl acrylate or methacrylates as a modifier. The polymerization is conducted in the presence of a catalytic amount of a trialkyl oxonium salt of an HMF 6  acid wherein M is an element selected from the group consisting of phosphorus, arsenic and antimony. The polymers are useful as tougheners for unsaturated polyester resin systems.

BACKGROUND OF THE INVENTION

Copolymerizations of epichlorohydrin with glycidyl esters ofethylenically unsaturated acids or ethylenically unsaturated epoxides toproduce solid elastomers which contain vinly unsaturation have beendisclosed previously in U.S. Pat. No. 3,285,870 and 3,158,591. The priorart teaches preparation of trialkyl oxonium salts of HMF₆ wherein M isan element selected from the group consisting of phosphorus, arsenic andantimony (U.S. Pat. No. 3,585,227) that are useful as catalysts forpreparation of rubbery polyepihalohydrins (U.S. Pat. No. 3,850,857);and, when water or a glycol is employed as reactant, liquidhydroxyl-terminated epihalohydrin polymers (U.S. Pat. No. 3,850,856.

SUMMARY OF THE INVENTION

Terminally unsaturated liquid epihalohydrin plymers have the formula##STR1## wherein Y is hydrogen or alkyl, X is 2 to 10 and G is apolymeric backbone comprising units of at least one epihalohydrin,optionally together with at least one other epoxide. Polymers areprepared by polymerization of an epihalohydrin in the presence of acatalytic amount of a trialkyl oxonium salt of an HMF₆ acid wherein M isan element selected from the group consisting of phosphorous, arsenicand antimony, and in the presence of hydroxyalkyl acrylates ormethacrylates. Unsaturated polyester molding compositions containingthese terminally unsaturated polymers have improved toughness whensuitably cured.

DETAILED DESCRIPTION

This invention discloses vinyl terminated polyepihalohydrins of lowmolecular weight. The polymers may be used as a toughener forunsaturated polyester resin systems.

The prior art described in U.S. Pat. No. 3,850,856 is a process ofmanufacturing hydroxyl terminated poly(epichlorohydrins) by cationicpolymerization using triethyloxonium hexafluorophosphate (TEOP) as theinitiator and in the presence of a controlled amount of water orethylene glycol.

The invention disclosed herein is a process which differs from the priorart in that the products of this invention are low molecular weightpoly(epihalohydrins) which are not only viscous liquids at rooomtemperature but also contain terminal vinyl groups prepared bypolymerizing an epihalohydrin in the presence of a trialkyl oxonium slatof a hexafluorometallic acid catalyst and hydroxy alkyl acrylates ormethacrylates.

The terminally unsaturated liquid epihalohydrin polymers have theformula ##STR2## wherein Y is hydrogen or methyl and X is 2 to 10,preferably 2 to 4. G is a polymeric backbone comprising units of atleast one epihalohydrin optionally together with at least one otherepoxide such as those having the formula ##STR3## wherein all R radicalsare selected from the group consisting of hydrogen, alkyl and alkenylradicals containing 1 to 10 carbon atoms, more preferably 1 to 5 carbonatoms, alkoxyalkyl radicals containing 2 to 10 carbon atoms morepreferably 2 to 6 carbon atoms, phenoxyalkyl radicals wherein the alkylgroup contain 1 to 6 carbon atoms, and phenyl radicals, and at least oneof said R radicals is hydrogen. Even more preferably all R radicals areselected from the group consisting of hydrogen and alkyl radicalscontaining 1 to 3 carbon atoms, and at least one of said R radicals ishydrogen. Examples of suitable epoxides include alkylene oxides such asethylene oxide, propylene oxide, cis-and trans- but preferablycis-butene-2-oxide, butene-1-epoxide, cis- and trans-pentene-2-oxide,cis- and trans-hexene-2-oxide, cis- and trans-hexene-3-oxide, and thelike; phenyl akylene oxides such as styrene oxide and the like; andglycidyl ethers such as methyl glycidyl ether, ethyl glycidyl ether,methylethyl glycidyl ether, butyl glycidyl ether, phenyl glycidyl ether,and the like. Normally in amounts up to 50 weight percent of the epoxymonomer. Excellent results were obtained with ethylene oxide andpropylene oxide. Also, unsaturated glycidyl ethers of the generalformula ##STR4## where R is an ethylenically unsaturated radical such asvinyl, allyl, alkenyl and the like. Typical glycidyl ethers includevinyl glycidyl ether, allyl glycidyl ether, butenyl glycidyl ether,4-vinylcyclohexyl glycidyl ether, abietyl glycidyl ether,cyclohexenylmethyl glycidyl ether, o-allyl-phenyl glycidyl ether isamounts up to 20 weight percent of the epoxy monomers. While theunsaturated glycidyl ethers are generally preferred, useful copolymersmay also be made with monoepoxides of dienes or polyenes such asbutadiene, methylene monoxide, chloroprene monoxide,3,4-epoxyl-1-pentene, 4,6-epoxy-2-hexene, 2-epoxy-5, 9-cyclododecadiene,and the like. Alkylene oxides are preferred "other epoxides", withethylene oxide, propylene oxide glycidyl acrylate and methacrylate andallyl glycidyl ether being especially useful. Prepared epihalohydrinsare epichlorohydrin and epibromohydrin, with epichlorohydrin beingespecially useful.

The terminally unsaturated epihalohydrin liquid polymers of the presentinvention are prepared using the catalyst described in U.S. Pat. Nos.3,585,227, 3,850,856 and 3,850,857 but in the substantial absence ofwater or glycol. The catalyst is a trialkyl oxonium salt of ahexfluorometallic acid, HMF₆ wherein M is an element selected from thegroup consisting of phosphorus, arsenic and antimony, such acids beingHPF₆, HAsF₆, and HSbF₆. A particularly economical method of preparingthese catalysts is described in the aforementioned U.S. Pat. No.3,585,227. This process entails mixing a solution of and HMF₆ acid witha dialkyl ether and an epoxide selected from the group consisting ofalkylene oxides and halogen-substituted alkylene oxides. The etheremployed in said process determines the alkyl groups present in theoxonium salt and one will select the ether for this purpose. Suitabledialkyl ethers include dimethyl ether, methyl ethyl ether, diethylether, dipropyl ether, ethyl propyl ether, di-n-butyl ether, di-n-amylether dihexyl ether, di-2-ethylhexyl ether and the like.

The preferred catalyst for use in the present process is triethyloxoniumhexafluorophosphate (TEOP)

    (C.sub.2 H.sub.5).sub.3 O.sup.+ PF.sub.6.sup.-

which is easily handled, stable crystalline salt. The amount of catalysttypically will vary from about 0.001 to about 1.0 weight part, forexample, 0.02 to 0.1, per 100 weight parts of epoxide monomer beingpolymerized. The preferred catalyst amount is from about 0.004 to about0.025 weight part per 100 weight parts of epoxide monomer. Of course,the exact amount of catalyst in any particular polymerization recipewill depend upon the specific HMF₆ salt used as well as the mode ofpolymerization, reaction temperature, and the like.

The vinyl-containing liquid polyepihalohydrins are prepared by thecationic polymerization of epihalohydrins using TEOP as the initiatorwith controlled amounts of a chain transfer agent selected fromhydroxyalkyl acrylates and hydroxyalkyl methacrylates. The amount ofchain transfer agent controls the vinyl content, the molecular weightand viscosity of the product. Usually, the amount employed can be in therange of 0.01 to 10 parts in weight based on one hundred parts ofmonomers employed. The preferred range is 0.01 to 5 parts.

The hydroxy alkyl acrylates and methacrylates have the formula ##STR5##wherein Y is hydrogen or methyl, and X is from 2 to 10, preferably 2 to4. Typical examples include 2-hydroxy ethyl acrylate, 3-hydroxy propylacrylate, 3-hydroxy propyl methacrylate, 2-hydroxy ethyl methacrylate,and the like. The actual number of terminal unsaturated groups may varyfrom about 1 to about 2 per polymer molecule. The amount of hydroxyalkyl acrylate or methacrylate typically will vary from about 0.01weight part to about 30 weight parts per 100 weight parts of epoxidemonomer, more preferably from about 1.0 to about 15 per 100 weight partsof epoxide monomers.

The reaction may be carried out at a reaction temperature of 20° to 100°C., preferably in the range of 30° to 80° C. The initiator, TEOP, whichis usually dissolved in methylene chloride may be charged to the reactorwith one shot, or incrementally batched in, or preferably, metered in ata constant rate over a span of 1 to 15 hours. The amount of initiator,TEOP, used in the reaction affects the reaction conversion and the yieldof product per unit weight of initiator employed.

A typical polymerization technique is as follows. The epoxide monomer(s)and hydroxyalkyl acrylate or hydroxyalkyl methacrylate are charged to astirred reactor and preheated to about 40° C. to 80° C. (althoughreaction temperature may vary from about 0° C. to about 110° C.). Thecatalyst is added neat or as a solution in a solvent such as methylenechloride. The catalyst may be added all at once but is preferably addedincrementally or continuously during polymerization to enable bettercontrol of reaction rate and temperature. An inert polymerizationsolvent of diluent is not required but may be useful to promoteefficient mixing and temperature control (the reaction is exothermic).Suitable solvents and diluents include benzene, toluene, hexane,cyclohexane, chlorobenzene and carbon tetrachloride. Reaction timenormally may be from about 1 to 20 hours or more. Reaction pressure istypically autogeneous, but superatmospheric pressures up to 10atmospheres or more may be employed with the more volatile monomers andsolvents/diluents. The reaction may be shortstopeed at a desired timeusing a solution of ammonium hydroxide in isopropanol. If a solvent ordiluent has been used, the polymer may be recovered by methods known tothe art, such as in a thin film evaporator. Any antioxidant such astetrakis[methylene(3.5-,di-tert-butyl-4-hydroxycinnamate)]methane astabilizer such as phenothiazine, tert-butyl catechol, and methylhydroquinone may be added after shortstopping.

The terminally unsaturated epihalohydrin polymers produced by the abovemethod will vary from fluid liquids to thick semi-solids having typicalnumber average molecular weights (M_(n)) from about 100 to about100,000. The polymers of this invention will typically have Brookfieldviscosity ranging from about 10 Pa.S to about 16,000 Pa.S at 27° C.

These characteristic features enable this material to be particularlyuseful as a toughener for unsaturated polyester resins system because itco-cures with the unsaturated polyester in addition to its easyhandling, and has good compatibility with the resin system.

The vinyl terminated polyepihalohydrin of this invention will beparticularly useful in the system disclosed and described in U.S. Pat.No. 4,101,604, wherein the molding compositions contain an unsaturatedpolyester resin, the vinyl terminated polyepihalohydrin of thisinvention, a polymerizable monomer and optionally, reinforcing fibers,catalyst thermoplastic polymers, thickening agents and fillers asdisclosed in said patent. The polymers of this invention also find usein castable compositions used as caulks, sealants and the like, asdisclosed in U.S. Pat. No. 3,925,330, wherein the compositions comprisethe vinyl terminated polyepihalohydrin of this invention, polymerizablevinyl monomer, and a free radical catalyst system. These materials willalso find use in forming co-curing compositions with amine terminatedliquid polymers of the nature described in U.S. Pat. No. 4,058,657.Further uses including a particular application of these vinylterminated polyepihalohydrin will be in the preparation of printingplates described in U.S. Pat. No. 4,137,081, wherein the compositionscomprise the vinyl terminated polyepihalohydrin of this invention, atleast one ethylenically unsaturated monomer, and a photo initiator.

The following examples illustrate the present invention more fully.

EXAMPLES 1 to 4

A series of experiments was carried out in sealed glass reactors. Theprocedure called for the initial charging of epichlorohydrin, hydroxyethyl acrylate or methacrylate, and solvents. The reactors were placedin a tumbler for agitation in a constant temperature bath, set at 50° C.for 20 minutes. The reaction run in the 50° C. bath was kicked-off withthe initial injection of 5 ml. of TEOP solution by incremental additionof 1 ml. of TEOP solution on the hour, every hour, for 4 hours. Thereaction continued for 11/2 hour and was shortstopped with 3 ml. of 1 to4 mixture in volume ratio of ammonium hydroxide-isopropyl alcohol. Therecipe and resultant data are listed in TABLE 1.

                  TABLE 1                                                         ______________________________________                                        VINYL CONTAINING LIQUID                                                       POLYEPICHLOROHYDRINS                                                          RUN NO.         1       2       3     4                                       ______________________________________                                        Recipe                                                                        Epichlorohydrin, grams                                                                        500     500     500   500                                     HEA, grams.sup.(1)                                                                            5       15      0     0                                       HEMA, grams.sup.(2)                                                                           0       0       5     15                                      TEOP, grams     0.127   0.127   0.127 0.127                                   Methylene chloride, ml                                                                        5       5       5     5                                       Short-Stop Solution, ml                                                                       3       3       3     3                                       Results                                                                       Conversion      50.1    47.6    45.2  36.9                                    Product Viscosity                                                             B. Viscosity, pa. S @27° C.                                                            283.2   46.5    539.2 156.4                                   ______________________________________                                         .sup.(1) HEA; 2hydroxy ethyl acrylate                                         .sup.(2) HEMA; 2hydroxy ethyl methacrylate                               

I claim:
 1. A terminally unsaturated liquid epihalohydrin polymer havingthe formula ##STR6## wherein Y is hydrogen or methyl, X is 2 to 10 and Gis a polymeric backbone obtained by homopolymerizing an epihalohydrin,copolymerizing two or more epihalohydrins, or copolymerizing anepihalohydrin with a vicinal epoxide.
 2. A polymer of claim 1 whereinsaid epihalohydrin is epichlorohydrin and said polymer has a numberaverage molecular weight from about 100 to about 100,000.
 3. A polymerof claim 2 wherein said backbone G also contains copolymerized units ofat least one other epoxide having the formula ##STR7## wherein each R isselected from the group consisting of hydrogen, alkyl, alkoxyalkyl andphenyl radicals, but at least one R is hydrogen.
 4. A polymer of claim 3wherein said other epoxide is an alkylene oxide.
 5. A polymer of claim 4wherein said alkylene oxide is ethylene oxide or a propylene oxide.
 6. Apolymer of claim 2 wherein said polymer has a number average molecularweight M_(n) from about 100 to about 100,000.
 7. A polymer of claim 2wherein Y is hydrogen and X is 2 to
 4. 8. A polymer of claim 2 wherein Yis methyl and X is 2 to
 4. 9. A polymer of claim 2 wherein said backboneG also contain copolymerized units of at least one other epoxide of theformula ##STR8## wherein R is an ethylenically unsaturated radical. 10.A process for the manufacture of a terminally unsaturated liquidepihalohydrin polymer which comprises polymerizing said epihalohydrintogether with a hydroxyalkyl acrylate or methacrylate in the presence ofa catalytic amount of a trialkyl oxonium salt of an HMF₆ acid wherein Mis an element selected from the group consisting of phosphorus, arsenicand antimony, and said polymer has the formula ##STR9## wherein Y ishydrogen or methyl, and G is a polymeric backbone comprising polymerizedunits of at least one epihalohydrin.
 11. A process of claim 10 whereinsaid epihalohydrin is epichlorohydrin, and said HMF₆ acid is HPF₆.
 12. Aprocess of claim 11 wherein the hydroxyalkyl acrylate is 2-hydroxylethyl acrylate or hydroxyl ethyl methacrylate.
 13. A process of claim 12wherein said polymerization is carried out at a temperature in the rangeof 0° C. to 110° C., and said backbone G also contains polymerized unitsof at least one other epoxide having the formula ##STR10## wherein eachR is selected from the group consisting of hydrogen, alkyl, alkoxyalkyl,phenyl and unsaturated radicals, but at least one R is hydrogen.
 14. Aprocess of claim 13 wherein the trialkyloxonium salt of HPF₆ istriethyloxonium hexafluorophosphate.
 15. A process of claim 14 whereinsaid other epoxide is an alkylene oxide.
 16. A process of claim 15wherein said alkylene oxide is ethylene oxide or propylene oxide.
 17. Aprocess of claim 16 wherein R is hydrogen.
 18. A process of claim 10wherein said epihalohydrin is epichlorohydrin, and said HMF₆ acid isHAsF₆.
 19. A process of claim 10 wherein said epihalohydrin isepichlorohydrin, and said HMF₆ acid is HSbF₆.